Localization of drug-resistant epilepsy using chemical exchange saturation transfer and magnetic resonance spectroscopy

This study investigates the efficacy of two advanced magnetic resonance technologies, proton magnetic resonance spectroscopy (1H MRS) and chemical exchange saturation transfer (CEST), for the precise detection of epileptic foci through the quantification of glutamate in a patient with drug-resistant epilepsy. A 21-year old female patient with drug-resistant epilepsy was examined using magnetic resonance imaging (MRI), MRS, and CEST with a 3.0-T MRI scanner with an 8-channel phased array head coil. Despite the absence of identifiable lesions on conventional MRI scans, CEST identified regions of high glutamate concentration in the left hippocampus, consistent with an epileptic focus. These results were confirmed with MRS. The findings of this investigation indicate that CEST is an effective method for the detection of high levels of glutamate, which correspond with epileptic foci. We therefore propose that CEST and MRS be incorporated into the standard diagnostic protocol used for patients with drug-resistant, MRI-negative epilepsy.